It turns out it is also useful to be able to perform other operations
on a file created while running as a different uid (eg, write things
to that file), and possibly to do this to a file that already
exists. This patch adds an optional hook function to the renamed (for
more accuracy of purpose) virFileOperation; the hook will be called
after the file has been opened (possibly created) and gid/mode
checked/set, before closing it.

As with the other operations on the file, if the VIR_FILE_OP_AS_UID
flag is set, this hook function will be called in the context of a
child process forked from the process that called virFileOperation.
The implication here is that, while all data in memory is available to
this hook function, any modification to that data will not be seen by
the caller - the only indication in memory of what happened in the
hook will be the return value (which the hook should set to 0 on
success, or one of the standard errno values on failure).

Another piece of making the function more flexible was to add an
"openflags" argument. This arg should contain exactly the flags to be
passed to open(2), eg O_RDWR | O_EXCL, etc.

In the process of adding the hook to virFileOperation, I also realized
that the bits to fix up file owner/group/mode settings after creation
were being done in the parent process, which could fail, so I moved
them to the child process where they should be.

* src/util/util.[ch]: rename and rework virFileCreate-->virFileOperation,
  and redo flags in virDirCreate
* storage/storage_backend.c, storage/storage_backend_fs.c: update the
  calls to virFileOperation/virDirCreate to reflect changes in the API,
  but don't yet take advantage of the hook.

ACPI feature bit dropped: I asked internally if the -no-acpi option
had any meaning for IA64, and was told 'probably not'.

Fix multiple veth problem.
NETIF setting was overwritten after first CT because any CT could not be
found by name.
* src/openvz/openvz_conf.c src/openvz/openvz_conf.h: add the
  openvzGetVEID lookup function
* src/openvz/openvz_driver.c: use it in openvzDomainSetNetwork()

If the hostname as returned by "gethostname" resolves
to "localhost" (as it does with the broken Fedora-12
installer), then live migration will fail because the
source will try to migrate to itself.  Detect this
situation up-front and abort the live migration before
we do any real work.

* src/util/util.h src/util/util.c: add a new virGetHostnameLocalhost
  with an optional localhost check, and rewire virGetHostname() to use
  it
* src/libvirt_private.syms: expose the new function
* src/qemu/qemu_driver.c: use it in qemudDomainMigratePrepare2()

* src/conf/domain_conf.c: make function static
* src/conf/domain_conf.h: remove it from header

* src/util/pci.c: update 2 message on pciRead errors

This patch adds the mac_filter support to the macvtap device.

* tools/virsh.c (cmdCPUBaseline): Add an explicit "return" statement
after the "no_memory:" label.

* src/util/buf.c (virBufferStrcat): Do not skip va_end due to
an early return.

* src/util/qparams.c (new_qparam_set, append_qparams): Do not skip
va_end due to an early return.

* src/xen/xend_internal.c (xenDaemonDomainSetAutostart): Rewrite to
avoid dereferencing the result of sexpr_lookup.  While in this
particular case, it was guaranteed never to be NULL, due to the
preceding "if sexpr_node(...)" guard, it's cleaner to skip the
sexpr_node call altogether, and also saves a lookup.

This patch sets or unsets the IFF_VNET_HDR flag depending on what device
is used in the VM. The manipulation of the flag is done in the open
function and is only fatal if the IFF_VNET_HDR flag could not be cleared
although it has to be (or if an ioctl generally fails). In that case the
macvtap tap is closed again and the macvtap interface torn.

* src/qemu/qemu_conf.c src/qemu/qemu_conf.h: pass qemuCmdFlags to
  qemudPhysIfaceConnect()
* src/util/macvtap.c src/util/macvtap.h: add vnet_hdr boolean to
  openMacvtapTap(), and private function configMacvtapTap()
* src/qemu/qemu_driver.c: add extra qemuCmdFlags when calling
  qemudPhysIfaceConnect()

For __virExec() this is a semantic NOP except for when fork()
fails. __virExec() would previously forget to restore the signal mask
in this case; virFork() corrects this behavior.

virFileCreate() and virDirCreate() gain the code to reset the logging
and properly deal with the signal handling race condition.

This also removes a log message that had a typo ("cannot fork o create
file '%s'") - this error is now logged in a more generic manner in
virFork() (more generic, but really just as informative, since the
fact that it's forking to create a file is immaterial to the fact that
it simply can't fork)

* src/util/util.c: use the generic virFork() in the 3 functions

virFork() contains bookkeeping that must be done any time a process
forks. Currently this includes:

1) Call virLogLock() prior to fork() and virLogUnlock() just after,
   to avoid a deadlock if some other thread happens to hold that lock
   during the fork.

2) Reset the logging hooks and send all child process log messages to
   stderr.

3) Block all signals prior to fork(), then either a) reset the signal
   mask for the parent process, or b) clear the signal mask for the
   child process.

Note that the signal mask handling in __virExec erroneously fails to
restore the signal mask when fork() fails. virFork() fixes this
problem.

Other than this, it attempts to behave as closely to fork() as
possible (including preserving errno for the caller), with a couple
exceptions:

1) The return value is 0 (success) or -1 (failure), while the pid is
   returned via the pid_t* argument. Like fork(), if pid < 0 there is
   no child process, otherwise both the child and the parent will
   return to the caller, and both should look at the return value,
   which will indicate if some of the extra processing outlined above
   encountered an error.

2) If virFork() returns with pid < 0 or with a return value < 0
   indicating an error condition, the error has already been
   reported. You can log an additional message if you like, but it
   isn't necessary, and may be awkwardly extraneous.

Note that virFork()'s child process will *never* call _exit() - if a
child process is created, it will return to the caller.

* util.c util.h: add virFork() function, based on what is currently
                 done in __virExec().

Support virtio-serial controller and virtio channel in QEMU backend.
Will output
the following for virtio-serial controller:

-device
virtio-serial-pci,id=virtio-serial0,bus=pci.0,addr=0x4,max_ports=16,vectors=4

and the following for a virtio channel:

-chardev pty,id=channel0 \
-device
virtserialport,bus=virtio-serial0.0,chardev=channel0,name=org.linux-kvm.port.0

* src/qemu/qemu_conf.c: Add argument output for virtio
* tests/qemuxml2argvtest.c
  tests/qemuxml2argvdata/qemuxml2argv-channel-virtio.args: Add test for
  QEMU command line generation

Add support for virtio-serial by defining a new 'virtio' channel target type
and a virtio-serial controller. Allows the following to be specified in a
domain:

<controller type='virtio-serial' index='0' ports='16' vectors='4'/>
<channel type='pty'>
  <target type='virtio' name='org.linux-kvm.port.0'/>
  <address type='virtio-serial' controller='0' bus='0'/>
</channel>

* docs/schemas/domain.rng: Add virtio-serial controller and virtio
  channel type.
* src/conf/domain_conf.[ch]: Domain parsing/serialization for
  virtio-serial controller and virtio channel.
* tests/qemuxml2xmltest.c
  tests/qemuxml2argvdata/qemuxml2argv-channel-virtio.xml: add domain xml
  parsing test
* src/libvirt_private.syms src/qemu/qemu_conf.c:
  virDomainDefAddDiskControllers() renamed to
  virDomainDefAddImplicitControllers()

Remove virDomainDevicePCIAddressEqual and virDomainDeviceDriveAddressEqual,
which are defined but not used anywhere.

* src/conf/domain_conf.[ch] src/libvirt_private.syms: Remove
  virDomainDevicePCIAddressEqual and virDomainDeviceDriveAddressEqual.

* src/qemu/qemu_driver.c: qemudStartVMDaemon() fix typo in comment

* src/node_device/node_device_linux_sysfs.c(get_virtual_functions_linux):
Return "ret", rather than always returning 0.

Currently we just error with ex. 'virbr0: No such device'.

Since we are using public API calls here, we need to ensure that any
raised error is properly saved and restored, since API entry points
always reset messages.

We were accessing the wrong private data structure, which would
cause a segfault.

virGetLastError returns NULL if no error has been set, not on
allocation error like virSetError assumed. Use virLastErrorObject
instead. This fixes virSetError when no error is currently stored.

The commands updated are SetMem, SetMaxMem, SetVcpus, and PinVcpu.

Rework and simplification of teardown of the macvtap device.

Basically all devices with the same MAC address and link device are kept
alive and not attempted to be torn down. If a macvtap device linked to a
physical interface with a certain MAC address 'M' is to be created it
will automatically fail if the interface is 'up'ed and another macvtap
with the same properties (MAC addr 'M', link dev) happens to be 'up'.
This will prevent the VM from starting or the device from being attached
to a running VM. Stale interfaces are assumed to be there for some
reason and not stem from libvirt.

In the VM shutdown path, it's assuming that an interface name is always
available so that if the device type is DIRECT it can be torn down
using its name.

* src/util/macvtap.h src/libvirt_macvtap.syms: change of deleting routine
* src/util/macvtap.c: cleanups and change of deleting routine
* src/qemu/qemu_driver.c: change cleanup on shutdown
* src/qemu/qemu_conf.c: don't delete Macvtap in qemudPhysIfaceConnect()

* src/schemas/domain.rng: Replace tabs with 8 spaces

The QEMU JSON monitor changed balloon commands to return/accept
bytes instead of kilobytes. Update libvirt to cope with this

* src/qemu/qemu_monitor_json.c: Expect/use bytes for ballooning

* src/openvz/openvz_conf.c (openvzLoadDomains): Diagnose failure of
virUUIDFormat.

The recent commit to implement a python version of this function
didn't drop an explicit 'ignore' check in the generator, so this
never ended up in the bindings.

Silence a libtoolize warning.
*  configure.ac (AC_CONFIG_MACRO_DIR): Add.

* tools/virsh.c: add a command to compute a CPU baseline based on
  multiple CPU definitions in an XML chunk
* tools/virsh.pod: add it to the man page

There is no real leak here, but Coverity-Prevent thinks there is.
It does not see that while there are four ways to return from
vshCommandGetToken with VSH_TK_END, none of them results in allocation
of a result.
* tools/virsh.c (vshCommandParse): Add a (currently) useless VIR_FREE,
to ensure that we never leak when vshCommandGetToken returns VSH_TK_END.

* src/qemu/qemu_monitor_text.c (qemuMonitorTextAddUSBDisk): Free
command output buffer.

* tests/qemuxml2argvtest.c (testCompareXMLToArgvFiles): Handle malloc
failure.

* src/qemu/qemu_driver.c (qemuInitPasswords): Free pass-phrase buffer.

* src/qemu/qemu_monitor_text.c (qemuMonitorTextAddDevice): Free the
device name buffer.

* python/libvirt-override.c (libvirt_virConnectBaselineCPU): Don't leak
the xmlcpus buffer upon encountering a non-string list element.

* src/vbox/vbox_tmpl.c (vboxDomainDumpXML): Free vboxCallback buffer
upon OOM.

* src/conf/node_device_conf.c (virNodeDevCapScsiHostParseXML):
Free the "nodes" buffer allocated by virXPathNodeSet.

* src/uml/uml_driver.c (umlMonitorCommand): This function would
sometimes return -1, yet fail to free the "reply" it had allocated.
Hence, no caller would know to free the corresponding argument.
When returning -1, be sure to free all allocated resources.